Quartz crystal geode

by Stephany
(Clovis California United states)

Found doing demolition on a house in chowchilla California. I think it’s a mud fossil or something there is sand that seems to keep coming from inside of it. The sediment layers on one end and the air sockets at the other tell me that it’s rare. I want to say it’s one of those rare rocks that help determine the age of evolution.